The present invention relates to a connection structure between an external connecting electrode and an electrode terminal of a power semiconductor module on an exterior case for power semiconductor module.
FIG. 9 is a cross-sectional explanatory view showing one example of a conventionally known connection structure between an electrode terminal and an electrode plate which is an exterior connecting electrode on an exterior case for power semiconductor module. The exterior case 82 for power semiconductor module includes an electrode terminal 83 and a terminal nut 85. One end of the electrode terminal 83 is electrically connected to an electrode plate 97 on the side of an outer surface of the case. The terminal nut 85 is used for fastening the electrode terminal 83 and the electrode plate 97 on an upper surface of the case. The electrode terminal 83 and the terminal nut 85 are integrally insert-formed together with a case body in a step for molding an exterior case 82. After the insert-forming, the electrode terminal 83 is bent such as to cover the terminal nut 85. The electrode terminal 83 is formed with a bolt-insertion hole 84 along its thickness direction. In a state in which the electrode terminal 83 is bent, a center axis of the bolt-insertion hole 84 coincides with a center axis of a female screw hole of the terminal nut 85 fixed on the side of an outer surface of the case.
To connect the electrode plate 97 with electrode terminal 83, the electrode plate 97 is positioned on the electrode terminal 83 such that a center axis of a bolt-insertion hole 98 formed along a thickness direction of the electrode plate 97 coincides with a center axis of the female screw hole of the terminal nut 85 and the bolt-insertion hole 84 of the electrode terminal 83, and in this state, a fastening bolt 89 is fastened to the terminal nut 85 through the electrode plate 97 and the electrode terminal 83. With this operation, the electrode plate 97 and the electrode terminal 83 are electrically connected to each other, and an electric signal generated in the power semiconductor module is introduced into the electrode plate 97 through the electrode terminal 83.
However, in the case of the conventional power semiconductor module having the connecting structure with the external connection electrode (i.e. electrode plate 97), it is necessary to fasten the fastening bolt 89 in a state in which the electrode plate 97 is held at a predetermined position. This makes it troublesome to position the electrode plate 97 with respect to the electrode terminal 83 when the number of electrode terminals included in the power semiconductor module is large. Especially when a large number of power semiconductor modules are used, or when the power semiconductor module is located at a position where it is difficult to position the electrode plate 97 to the electrode terminal 83, there is a problem that the working time to assemble power semiconductor module becomes longer.
It is an object of the invention to provide a connection structure between an external connecting electrode and an electrode terminal of a power semiconductor module on an exterior case for power semiconductor module, which is capable of using an existing power semiconductor module as it is, capable of easily positioning an external connection electrode with respect to an electrode terminal, and capable of realizing efficient assembling operation.
According to an aspect of the present invention, there is provided a power semiconductor module with a connection structure in which an electrode terminal whose one end is connected with an electric power semiconductor device which is resin sealed inside of the case, is exposed along an outer surface of a case for taking out electrode from the semiconductor device, and is electrically connected to an electrode for external connection disposed on the electrode terminal, wherein a female screw hole for screwing is provided on side of the outer surface of the case, a male screw member formed at its opposite ends with screw threads is threadedly engaged with the female screw hole through the electrode terminal.
A nut having the female screw hole may be embedded in the outer surface of the case, and the nut may be fixed to a lower surface of the electrode terminal.
The electrode terminal may have the female screw hole.
The male screw member may have different nominal diameters at opposite ends.
The male screw member may have threads at opposite ends of which directions are opposite from each other.
At least one nut may be fixed to a middle portion of the male screw member.
A middle portion of the male screw member may be formed with a discontinuous portion having no screw thread.
The male screw member may be threadedly engaged with the female screw hole through a plurality of electrode terminals.